1. Field of the Invention
Aspects of the present invention relate to a flowing device for an optics-based methanol sensor, and more particularly, to a flowing device that supplies methanol to an optics-based methanol sensor that optically measures the concentration of methanol.
2. Description of the Related Art
Direct liquid feed fuel cells mainly use methanol as fuel. When a high concentration of methanol is supplied to an anode of a direct liquid feed fuel cell, the efficiency of the fuel cell in terms of electricity generation is greatly reduced due to cross-over of fuel through the electrolyte membrane (hydrogen ion exchange membrane) from the anode to the cathode. Therefore, diluted methanol with a concentration of 0.5 to 2M (2 to 8 vol. %) is generally used.
A direct liquid feed fuel cell system includes a fuel tank where methanol in a high concentration or pure methanol is stored. A diluted fuel having a uniform concentration and made by mixing the methanol from the fuel tank with water, such as recovered water or water from a water tank, is supplied to an anode electrode. A methanol sensor for detecting the concentration of the mixed fuel is desirable.
An optics-based sensor having a interior flow channel that supplies a sample to the optics-based sensor has been disclosed in U.S. Pat. No. 6,183,696. However, the flow channel can interfere with an optical path of the sensor, and the inner structure of the sensor is complicated.